将UI操作委托给ViewModel执行

我也会投票给你的滚动查看器一个AttachedProperty。

我创建了以下附加属性,将滚动绑定到一个布尔变量的末尾。

public static class ScrollViewerBehavior
    {
        public static readonly DependencyProperty ScrollToRightEndProperty =
            DependencyProperty.RegisterAttached("ScrollToRightEnd", typeof (bool), typeof (ScrollViewerBehavior),
                                                new PropertyMetadata(false, OnScrollToRightEndPropertyChanged));

        public static bool GetScrollToRightEnd(DependencyObject obj)
        {
            return (bool) obj.GetValue(ScrollToRightEndProperty);
        }

        public static void SetScrollToRightEnd(DependencyObject obj, bool value)
        {
            obj.SetValue(ScrollToRightEndProperty, value);
        }

        private static void OnScrollToRightEndPropertyChanged(DependencyObject sender,
                                                              DependencyPropertyChangedEventArgs e)
        {
            var sv = sender as ScrollViewer;
            if (sv == null) return;

            if ((bool) e.NewValue)
            {
                sv.ScrollToRightEnd();
            }
            else
            {
                sv.ScrollToLeftEnd();
            }
        }
    }

您可以在XAML中使用此附加属性。。。

<ScrollViewer ... local:ScrollViewerBehavior.ScrollToRightEnd="{Binding IsScrolledToEnd}" ... />

或者,如果您想将操作委托保存为问题中的操作委托,可以在上面的OnScrollToRightEndPropertyChanged方法中执行以下操作。

.....
var viewModel = sv.DataContext as YourViewModel;
if (viewModel != null)
{
    viewModel.ScrollAction = () => sv.ScrollToRightEnd();
}
.....